INCREASED SUSCEPTIBILITY OF LDL TO OXIDATION IN PATIENTS WITH CAROTIDATHEROSCLEROSIS

Background and Aim: An increased susceptibility of LDL to oxidation ha s been related to the genesis of vascular disease. The purpose of this study was to investigate whether this is atherogenic in patients with carotid atherosclerosis and free from other major risk factors. Metho ds: Seventy-two subjects underwent echo-color-Doppler examination of t heir carotid arteries. None were hypertensive hyperlipidemic, diabetic or obese, nor suffered from major chronic diseases. Forty were free f rom carotid lesions (Controls), whereas thirty-two subjects had eviden ce of carotid atherosclerosis (Cases). Fourteen young healthy individu als acted as a further control (Young controls). The susceptibility of LDL to oxidation was tested in vitro by monitoring the kinetics of co njugated diene formation induced by the free radical generator 2,2'-az obis (amidinopropane) dihydrochloride (AAPH). Their fatty acid composi tion and the vitamin E con tent were also measured Results: The result s showed a significantly greater peroxidation rate in cases than in co ntrols (p=0.003), whereas no significant difference was found for the lag phase. The peroxidation rate for the whole population was signific antly correlated with the LDL polyunsaturated fatty acid content (r=0. 31, p=0.01). An inverse correlation was also observed between this rat e and the 18 :1/18 :2 ratio in LDL (r=-0.36, p=0.004). A longer lag ph ase and a higher LDL vitamin E content were found in young controls as compared with the other two groups (p<0.0001). Conclusions: The study suggests that LDL oxidation might play a significant role in atheroge nesis. It also indicates that the fatty acid composition of LDL may de termine their in vivo oxidizability. (C) 1998, Medikal Press.